Oil-cooled transformer



April J. ROOTHAAN OIL COOLED TRANSFORMER 2 Sheets-Sheet 2 Filed Sept. 22, 1926 Patented Apr, 30 1929 *PMENT- OFFICE y er ers, ner esjfeneilmvn.

oI -cooLEiJ T AN'SFORMERE -Apli lication filed September 22, '1926, Scria1' No. 136,990, and at Great Britain September 22,1925:

. This invention relates to oil-cooled electric 'itransformers provided' with external air cooled tubes through which and-the casing-of the transformer, oil can circulateautomaticallyby'reason of the difference in temperature'thereof =intheylowerand upper portions of. the tubes; "In such anarrangelnent i-the rate of cooling: of ithe :oil in the tubes is slownso' that fthe rate of circulation of the bitthrough the tubes-and the'cas'ing is also 5. I; if? '3 7 ."I :Now the present invention has for its object to eflectthecooling of the oil in the tubes in a quicker and more effective manner than heretofore and thus to produce a quicker circulation thereof through-the tubes and transformer casing.--- 1 Y 1: 3

J For?tl's'purpose, in an oil-cooled transformer. arrangement according to the present invention, the transformer 1 casing is provided externally with. a number of oil circulatingtubes of larger diameter than heretoforsusuahand throu'gheach of-which extend a-numbor of ducts connected'to plates and communicating with upper and :lower headers through which: and the vducts a cooling medium can be caused to flow so as to effect-rapid cooling of the oil 'in COIltlCbWltll the 4 ducts, each tube having. inlet and outlet branches near its ends and an uninterrupted bore from end to end. The cooling medium whichmay' conveniently be water, maybe forced under pressure through the ducts in .theopposite direction to that in whi ll llllB oil flows through the tube.

*I'n the accompanyingillustrative drawings, Figs. 1 and 2 are elevations at right angles 'to' one another and Fig. 3 a plan showing one construction of oil-cooled transformer embodying the present invention. Fig. 4 is a longitudinal central section, showing, to a larger scale, one of the oil tubes with associated cooling ducts and headers employed with the transformer casing. Fig; 5 is-an underside view of part of the lower header and of the tube with associated ducts. V

In the example shown a is the casing of an oil cooled transformer and 6 external vertical oil circulating tubeseach of which is provided with inlet and outlet branches 6 and b respectively by WhiCll'it is secured to the casing, the tube extending throughout the greater'part of the height of the casing. Each of the tubes 5 has, as shown in Fig. 4, an uninterrupted bore and is provided internally with a number of ducts c which extend The upper tube plate 0 cover 9 so that readyaccess to the ducts-c when'desired. .As will be seen the arrangement is such a hole 5 'branch 6 b may be provided with holes b b throughoutithe length of the tube, are carriedby tube plates 0 and c? and communicate with lowerand upper headerscl and e provided with water-inlet and outlet branches d and c grespectively. a

I is provided with a fiange'c by which it is secured in place between-the upper. end of-the tube 1 and the upper header 6, whilst the-lower tube platec 1s fitted to slide in a liquid tight manner within the lower end wall ofthe tube and the ad- :jacent -headerd which is bolted :to'the lower end of the tube, 7 being an interposed packing ring that is compressed-in place by the header to ensure a liquid tight'joint between the tube plate 0 and thetube end wall and header. In this way expansion and contractron-of the ducts 0 is provided 'for. The lower header d is provided witha removable can be gained that when the transformer is in action, heated .oil withinthe casing can flow downward freely through the-tubes Z) and be quickly cooled by contacuwitlrthe ducts 0 through which cooling fluid is-caused to flow in an upward direction. Each tube 6 may be provided with for attachment of an air cock, each for attachment of a thermometer and pressure gauge respectively, each upper header e may be; provided with a hole 6 for the insertion ofta thermometer and with a hole 6 -for connection to an air cock and the cover 9 o'f'e'aclr lower header d may be provided 'with a hole 65 for, attachment of a drain cock.

The number and diameter of the tubes 6 employed and the number of ducts 0 used in each tube can be varied to suit requiren'lent.

- What I claim is 1. An oil-cooled electric transformer comprising a casing, external cooling tubes each connected at-its upper and lower ends to said casing and through :which oil'can circulate in an automatic and uninterrupted manner whenthe-transformer action, a plurality of cooling ducts arranged within each externalcooling tube and through which a cooling medium tan be caused to flow, upper and lower headers secured to the upper and lowerendsrespectively of said cooling tube andcommunicating with said cooling ducts and upper and lower plates to which the ends of saidcooling ducts are connected, one of said plates being held between one end of said external =cooiingt tube and theradjacent header and "the other plate being fittd to slide in a liquid-tight manner within the other end of said external cooli tube.

2. An oil-cooled electric trans ormer comprising a casing, external cooling tubes-each connected at its upper and lower ends to said asingaand through whichoilcan.circulatein an automatic and uninterrupted manner whenthe transformer :is in action, a plurality ofvcoolingwducts arranged .within each external cooling tube. and through which .a cooling mediumcanbe caused to flow, upper and lower headers secured to the upper and lower endsof'said cooling tube and the lower of which isp'rovided with aremovable cover one of said plates being secured between-one end ofsaid cooling tube .and the adjacent hea'derand the other plate. being arranged to slide endway's-inlisaidioooling tube, and a packing ring surrounding thelatter plate an d adapted to be compressed between the adjacent; ends of sthe cooling' tube and its companion header and around the latter plate.

3 Eor anoil-cooled transformer, a cooling arrangement comprising :a cooling tube having lateral inlet andoutlet branchesifor attachment to .a transformer casing, headers secured to the ends of' said tube and-having branches for attachment to .a source of cooling fiuid,uducts r-extending longitudinally througlrsaid tube, plates to :which the ends of said tubesare secured, one of said plates being secured between one end of said tube and the adjacent header, and the'other plate being arranged to slide in a liquid tight 1nan nerin said tube, a packing ring surrounding the latter-plate and arranged to be compressed-between the adjacentend of said tube and header, and-a removable cover secured to one of said headers.

. 4. For an'oil-cooled transformer, a cooling arrangement comprising a cooling tube having lateral inlet and outlet branches for attachment to a transformer casing headers secured to the ends of said tube and having branches for attachment to a source of cooling fluid, ducts extending longitudinally through said tube, plates to which the ends of said tubes are secured, one of said plates being secured between one end of said tube and the adjacent header, and the other plate beingarranged to slide in a liquid tight manner in said tube, and a removable cover secured to one of said headers.

5. An oil cooled electric transformer comprising a casing enclosing the transformer, external tubes each connected at its upper and lower ends to said caing and through which oil can circulate in an automatic and uninterrupted manner when the transformer is in action, a plurality of straight parallel plain cooling ducts extending through said tube, and headers arranged above and below the upper and lower ends of each tube and r all thecooling ducts in parallel.

6. An oil cooled electric transformer comprising a casing enclosing the trauisformer,

external tubes each connected atits upper and :lower ends to said casing and through which oil can circulate in an automatic and' uninterrupted manner when the transformer is in action, headers arranged above and below the upper and lower ends of each tube, tube plates separating the interior of the tube from the interiors of said headers and a plurality of straight parallel cooling tubes carried by said tube plates and in communication with the interiors of said headers and through which and said headers a cooling medium can be caused to flow, one of said tube plates being adapted to admit of expansion and contraction of said ducts.

7. An oil cooled electric transformer comprising a casing enclosing the transformer, external tubes each connected at .its upper and lowerends to said casing and through which oil can circulate in an automatic and uninterrupted manner 'when the transformer i s in action, headers arranged above and be low the npperand lower ends of each tube, a stationary tube plate separating the interior of one header from the interior of said tube,--a movable tube plate arranged to slide in a fluid tight manner in said tube and to separate the interior of said tube from the interior of the second heater, .and straight plain parallel cooling ducts extending through said tube and connected to said tube plates and through which and said headers a cooling medium can be caused to flow.

8. An oil cooled transformer comprising a casing for said transformer. external tubes each connected at its upper and lower ends to said casing and through which oil can circulate in an automatic and uninterrupted manner when the transformer is in action, readers connected to the upper .and lower ends of said tube, a stationary tube plate separating the upper header from the interior of said tube, a movable tube plate arranged toslide in a liquid tight .manner in said tube below the lower oil outlet'therezfrorn and to separate the interior of said tube from the interior of the lower header, straight parallel duct-s connected to the tube plates and through which and the headers, 21 cooling medium can be caused to flow and a cover detachably connected to the lower side of said lower header.

Signed at London, this 26th-dayof August, 1926.

JAN ROOTHAAN. 

